No abstract

Rapid identification of causative agents from positive blood culture media is a prerequisite for the timely targeted treatment of patients with sepsis. The GENECUBE (TOYOBO Co., Ltd.) is a novel, fully-automated gene analyzer that can purify DNAs and amplify target DNAs. In this study, we evaluated the ability of two newly developed GENECUBE assays to directly detect the nuc and mecA genes in blood culture medium; nuc is specific to Staphylococcus aureus , and mecA indicates methicillin resistance. We examined 263 positive blood culture samples taken at three hospitals from patients suspected of having staphylococcal bacteremia. The results were then compared with those obtained using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, antimicrobial susceptibility testing (Microscan system or Dry-plate EIKEN), and sequencing analysis. The GENECUBE assays had sensitivity and specificity of 100% in detecting both S . aureus and methicillin resistance in positive blood culture. The turnaround time of the examination was evaluated for 36 positive blood culture samples. The time between the initiation of incubation and completion of the GENECUBE examination was 23 h (interquartile range: IQR 21–37 h); the time between reporting of Gram stain examination and completion of the GENECUBE examination was 52 min (IQR 48–62 min). These findings show that the GENECUBE assays significantly reduce the assay time with no loss of sensitivity or specificity.

Swift uptake of Ru dyes and improvement of photovoltaic performances for dye-sensitized solar cells ͑DSC͒ are reported. Ru dyes such as black dye ͓͑C 4 H 9 ͒ 4 N͔ 3 ͓Ru͑Htcterpy͒͑NCS͒ 3 ͔ ͑tcterpy = 4,4Ј,4Љ-tricarboxy-2,2Ј:6Ј,2Љ-terpyridine͒ and N3 dye ͓cis-di͑thiocyanato͒-N,NЈ-bis͑2,2Ј-bipyridyl-4,4Ј-dicarboxylato͒ ruthenium ͑II͔͒ are adsorbed on nano-porous TiO 2 layers under a pressurized CO 2 atmosphere to bond Ru dyes on inner surfaces of TiO 2 in nano-porous layers effectively. The time needed for N3 dye adsorption under a pressurized CO 2 condition is drastically shortened to 30 min from 300 min needed for a dipping process. The amount of N3 dye molecules increases from 15 to 20 nmol/cm 2 /m when N3 dye is adsorbed under a pressurized CO 2 atmosphere. The pressurized CO 2 process increases short circuit current, fill factor, and open circuit voltage which are associated with better coverage of TiO 2 surfaces with dye molecules. They decrease surface traps of porous TiO 2 layers. This retards back electron transfers from TiO 2 layers to iodine in electrolytes and facilitates electron diffusion in TiO 2 layer. Measurement of the electron lifetime and electron diffusion coefficient in the cells supports the mechanism.

Dye-sensitized solar cells ͑DSCs͒ are solidified with gelators containing polyvinylpyridine and 1,2,4,5-tetra͑bromomethyl͒benzene. The photoconversion efficiencies are improved by new additives. LiI and t-butylpyridine are commonly added in electrolytes for increasing short-circuit current ͑Jsc͒ and open-circuit voltage ͑Voc͒. These additives inhibit our gel electrolyte precursors from solidifying. We found that new additives, combinations of acetic acid, and methylpyrimidine or methylbenzimidazole, do not inhibit the solidification and are effective for increasing both Jsc and Voc. These mechanisms are discussed in terms of electron diffusion coefficients, I 3 − ion diffusion coefficients, and charge-transfer resistances between counter electrodes and gel electrolytes.

No abstract